High pressure hydraulic piercing cylinder with integral booster and stripping means



May 30, 1961 T. F. NOVAK 2,986,057

HIGH PRESSURE HYDRAULIC PIERCING CYLINDER WITH INTEGRAL BOOSTER ANDSTRIPPING MEANS Filed Sept. 11, 1957 2 Sheets-Sheet 1 FE E K 1 J 4 H v/7/ :A 52

IN V EN TOR. 77/5090/25 F. A/o 144k MLQQw/V #7 77'ORNEY May 30, 1961 T.F. .NOVAK 2,986,057

HIGH PRESSURE HYDRAULIC PIERCING CYLINDER WITH INTEGRAL BOOSTER ANDST-RIPPING MEANS Filed Sept. 11, 1957 2 Sheets-Sheet 2 ENO Y9 ML RNEYINVENTOR N h WV. m w v w w i w 2 m6 w w w ...M am

I! 14 NIIIII'III rd u 5"! United States Patent HIGH PRESSURE HYDRAULICPIER'CING CYLIN- DER WITH INTEGRAL BOOSTER AND STRIP- PING MEANSTheodore F. Novak, La Grange Park, Ill., assignor to Danly MachineSpecialties, Inc., Chicago, Ill., a cor poration of Illinois Filed Sept.11, 1957, Ser. No. 683,312

8 Claims. (Cl. 83-133) My invention relates to a high-pressure,hydraulic, piercing cylinder and more particularly to an improved,high-pressure, hydraulic, piercing cylinder having an integral boosterand stripping means.

Hydraulic power cylinders for pushing a punch or the like through aworkpiece are known in the prior art. These assemblies are provided withan automatic means for holding a stripper plate against the work whilethe punches are being withdrawn or stripped from the work. One form ofsuch an assembly is disclosed in the patent to C. E. Novinger et al.,No. 2,758,652, issued August 14, 1956, for a hydraulic punch andstripper. In these punch and stripper assemblies fluid under pressuremoves a power piston and cylinder relative to each other to move thepunch holder toward the work. At the same time the fluid under pressuremoves a stripper plate into engagement with the work to hold the workfirmly in position during the punching operation. After the stripperplate engages the work and before the punches enter the work, it isnecessary to boost the pressure within the cylinder in order to drivethe punches through the work. To accomplish this in systems of the priorart a separate booster external to the piston and cylinder assembly isemployed. It will be appreciated that high-pressure pipes are requiredto carry fluid from the booster to the piston and cylinder assembly.This system of the prior art is expensive and the possibility existsthat leaks will develop under the action of the high-pressure fluid.

I have invented an improved hydraulic punch and stripper assembly whichis provided with an integral booster for raising the fluid pressure byan amount necessary to drive the punches through the work. My assembly'does not require the external booster employed in systems of the priorart. My system does not require that fluid under high pressure heconducted through any pipes external to the punch and stripper assembly.For this readevelop leaks than are the systems of the prior art.

One object of my invention is to provide a high-pressure,

hydraulic, piercing cylinder having an integral booster and strippingmeans.

Another object of my invention isto provide a high pressure, hydraulic,piercing cylinder which does not require the external booster of systemsof the prior art.

A further object of my invention is to provide a highpressure,hydraulic, piercing cylinder which does not require fluid under a highpressure to flow through any pipe external to the cylinder.

A still further object of my invention is to providela high-pressure,hydraulic, piercing cylinder which is less a'power chamber and with astripper chamber. I a stationarypower piston within the power chamberandj a movable stripper piston within the stripper chamben;

My stripper piston has a head, on which fluid admitted into the stripperchamber may act, and an end extending into a bore in the wall separatingthe cylinder chambers. Fluid under pressure admitted to the powerchamber on one side of the power piston head moves the cylinder assemblytoward the work. This fluid also acts on the small face of the piston tomove the piston into engagement with the stripper pins which hold astripper plate against the work; After the stripper plate contacts thework the increased resistance moves the stripper piston relative to-thecylinder to build up a back pressure in the power chamber and supplyline to actuate a sequence valve to admit fluid under pressure to thestripper chamher on the side of the stripper piston head in engagementwith the stripper pins. This fluid acts on the relatively large areaofthe stripper piston head to cause a buildup or boosting of the pressurein the power chamber through the medium of the smaller area face of theshipper piston son my assembly is less expensive and is less likely to ito provide the pressure required to drive the punches through the work.At the .same time, this fluid under pressure maintains the stripperplate in engagement with' the work; A check valve in the supply linesprevents this boosted pressurefrom backing up into the supply lines.

' When the punching operation is complete, direction of the fluid flowin the. supply lineis reversed, the punch is stripped from the work andthe assembly is returned to its initial position.

.In the accompanying drawings, to which reference is made in the.instant specification and which are to be read in conjunction therewithand in which like reference numerals are used to indicate like parts inthe various views Figure 1 is a schematic view of my high-pressure,piercing cylinder and its associated fluid system.

Figure 2 is a sectional view of my high-pressure, piercing cylindershowing therelative positions of the parts before a punching operationis begun.

Figure 3 is a sectional view of my high-pressure, pierc-li .ing cylindershowing the relative positions of the parts as the cylinder moves towardthe work.

Figure 4 is a sectional .view of my high-pressure, pierc ingcylindershowing the relative positions of the,

during the course of a punching operation.

Figure 5 is 'a sectional view of my high-pressure, piercing the returnstroke of the cylinder.

body It}.

An end cap 18,

her 12. p

' Thepress A punch-carrier tool head whichextends 'intoa' bore 42 formedin separator. '16,

Patented May 30, 1961..

ing cylinder showing the relative position of the parts dursecured toan' end of the body 10 by any convenient means such as bolting or thelike,- 1. closes the end of the power chamber 12. A'power piston rod 20passes through a bore 22 in cap 18. Cap 18 houses a power piston head 24formed on rod 20 within chain-1' with which our cylinder is usedincludes a frame, indicated generally by the reference character 26,having an upright heel block 28 on which we mount the i power piston rod20 by any convenient means (not shown). We provide frame 26 with a'guideway 32 on which the cylinder 10 rides inits movement toward and;away from the work. i i 34, secured to theend of body- 10 remote fromcap '18 by any. convenient means' 2 such as bolts 36, closes thestripper chamber 14 to house." a booster and stripperpiston 38 formedwith a rod r 3 From the foregoing it will be seen that a fluid underpressure admitted into chamber 12 on that side of head 24 which willcause body to move to the right as viewed in Figure 1, also will act onthe end face 44 of rod 40 to movi head 38 t h i t, as vi we 't fie e C iv'e'rsely; fluid pressure admitted tochamber14"betvveen headot stripperand booster piston38 and tool head 34 istran'sinittejd by rod 40 tochamber 12 th'r'ou'ghthe medi urn ofthe face 44. Owing to the relativelylargearea o f'head of stripper and booster piston38 with "respect tothis face; a multiplication of pressure results in the course oftransmissionof pressure by rod 40.

Bolts 46 screwedinto to'ol head 34 have smooth shanks 4s whichslidablysupport as trfipper plate 50foimovenient along shanks 481 Stripper pins52 extending through theto'ol head 34' and through the punch holder, tobe described hereinafter, are adapted 'to transmit pressureffomjstrjipper and booster pis'ton38 to stripper plate 50.

A' screw54'secures thepun'ch holder 56t o the tool head 34. purichholder'56 supports the tools such as punchesSS which are requiredto performthe necessary' operations on a'work piece 60 supported on the framebyany convenient means (not shown) known to the art. I form the stripperplate 50 with bores 62 through which punches 58 pass in the course of apunching operation.

Frame 26 also carries a guide 64 having bores 66 into which punches 58push slugs or piece parts 68 formed in the'course of a punchingoperation. Bores 66 are open to permit the slugs 68 to fall out of thedie to a scrap collector or the like (not shown).

'1 form rod20 and heel block 28 with a first passage 70 through whichfluid under pressure may be admitted tochamber 12 between head 24 andseparatingwali 16. A second passage 72 formed in rod 20 and in heelblock 28 provides a path for the flow of fluid to chamber 12 betweenhead 24am plate 18.

My fluidsupply system includes a motor 74, which drives a pump 76through the linkage 78 to draw fluid from a tank 80 through a pipe 82.Pump 76 supplies fluid under pressure to a pipe 84 to which I connect arelief valve 86 which permits the fluid to flow back intothe tank whenthe pressure within pipe 84 exceeds a predetermined pressure. A controlvalve, indicated generally by th e reference character 88.has a housing90 provided with a port 92 communicating with pipe 84. The valve spool94 includes respective heads 96 and 98 which, the central position ofspool 94 shown in Figure 1, close respective outlet port-s .100 and 102connected to pipes 104 and. 10 6. Spool 94 is adapted to be actuated inany convenient manner known to the art to moveto theleft or to the rightof the intermediate position shown in Figure 1. In the left position ofspool 94 a communication ,is established between supply pipe 84 and pipe104. At the sametirne fluid from pipe 106 is permitted to flow throughhousing 90 and thrpugh an outlet pipe 108 to the tank.

In the position of spool 94 to the right a communication is establishedbetween pipe 106 and supply pipe 84 while fluid in pipe 104 is permittedto flowthrough the valve body and through a pipe 110to the tank. Iconnect pipe 104 to one inlet port 112 of a pilot-operated check valveindicated generally by the reference character 114, having a housing 116formed with a chamber 118 provided with a seat 120. A spring 122normally seats the piston 124 of valve 114 on seat 120. A port 126formed in .housing 116 is adapted to admit fluid under pressure to thehousing to act on a piston 5128 which contacts piston 124 to liftthelbo'dy ofl seat 120. The pipe 127 connects port 126 to pipe 106.Thefluid acting on piston 128 moves the piston 124 upwardly, as viewedin Figure 1, to permit fluid in the chamber 12 to flow outwardly'through passage .70,' through a port 130 formed in'housing116 and pastseat 120 to pipe 104.

JI'hehydraulic system of my piercing cylinder includes a sequence valveindicated generally by the rererence character 132'having a housing 134formed with a port 136 for conducting fluid from a pipe 138, connectedto pipe 104, the chamber 140 formed by housing 134. A spring 142disposed in housing 134 normally positions the valve spool 144 to close'a' port 146 formed in the wall of the housing 134. A pipe 148 connectsport 146 to passage I'forrned bythe' cylirr'derbody '10. Passage" 150"atfords a communication between pipe 148 and chamber 14 be tween thestripper and booster piston 38 and tool head 34. A passage 152 formed inthe wall of housing 134 is adapted to connect port 136 with port 146 toby-pass the chamber 140. A spring 154 normally positions a ball 156against a seat 158 formed in passage 152 to close the passage. Spring154, ball 156 and seat 158 form a check valve for preventingthe flow offluid from port 136 to port 146 while permitting fluid to flow in thereverse direction from port 146 to port 136.

Apassage 160 formed in the wall of body 10 connects a passage l62leading into chamber 12 between head 24 and cap l8 with a bore 164leading into chamber 14 between dividing wall 16 and stripper andbooster piston 38.

Referring now'to Figures 1 and 2 to S, which latter figures illustratethe relative position of the parts at various poin ts in a punchingoperation, before an operation body 10 and power piston head 24 occupythe relative position shown in Figure 2. When a punching operation thespool 94 of valve 88 is shifted, by any convenient means known to theart, to the left as viewed Figure 1 to connect pipe 104 with supply pipe84. Atthe same time pipe 106 is connected to the tank through pipe 108.The direction of flow of fluid in this condition of valve 88 isindicated by the arrows in Figure 2. under pressure in pipe 104 urgespiston 124 upwardly as viewed in Figure 1 against the action of spring iilqwsthrough port 130 and passage 70 into chamher 1 2. This fluidadvances the stripper piston 40 to the right asviewed in Figures 1 and2. At the same time it moves cylinder body 10 to the right as viewed inthe figures to advance the stripper plate 50 and the punch assemblytoward the work 60. As is known in the art, the stripper plate 50engages the Work 60 before the punches 58. The increased resistance asthe stripper plate engages the work is transmitted through pins 52 andthrough the stripper piston to the fluid in chamber 12 between wall 16and piston head 24. As a result of this increased resistance thepressure of the fluid in pipe 104 builds up toicause a similar build-upin the chamber 140 ofthie valve 132. The relative position of the partsas the stripper plate engages the work is shown in Figure 3.

As the pressure within chamber 140 builds up spool 144 moves upwardly asviewed in Figure 1 to open port 146 to permit fluid to flow from pipe104 through pipe 138 and through chamber 140 to pipe 148. It will beseen that fluid from the supply pipe now flows into chamber 14betweenthehead ofstripper and booster piston 38 and the tool head 34. ,fThisflowof fluid produces two results.

, ;First, it acts on the face of stripper and booster piston 38 to shiftthe stripper and booster piston to the left as viewed in Figure 4 to,boost the pressure within the chamber 12 between; wall 16'andhead 24. Theamount by which the pressure of the fluid within chamber 12 increases isproportional to the relative areas of the face of stripper and tion whenthe pressure in chamber 12 between wall 16 head 24' is built up is shownin Figure 4. "Atthe end of the punching operation in order to returnment of the stripper piston under the action of this fluid relieves thebuilt-up pressure on the fluid between wall 16 and head 24. The pistonhead 38 continues its movement tothe right to engage the stripper pins52 to maintain stripping pressure on plate 50. At this point in thereturn operation the punches in the work cause a resistance to movementof cylinder body which results in a build up of pressure within pipe106. This pressure build up is transmitted through the fluid in pipe 127to piston 128 to move piston 124. upwardly as viewed in Figure 1 to openport 130 to permit fluid to flow out of chamber 12 through passage70 andport 130 to the tank through pipe 104. It will be remembered that spring122 returned piston 124 to seat 120 when spool 94. of valve 88 was movedtothe right to initiate a return operation. The direction of flow offluid during the beginning of a return operation is shown by the arrowsin Figure 5. After this connection of passage 70 to the tank, body 10moves away from the Work with tool head 56 to strip the punches from thework. When piston head 38 bottoms on tool head 34 the punches are fullystripped and oil continuing to flow into chamber 12 from passage 72moves the entire assembly away from the work to its .fullyretractedposition. The assembly is then ready for the next punching operation.

It will. be seen that I have accomplished the objects of my invention. Ihave provided a high pressure bydraulic .piercing cylinder with anintegral booster and stripping means. Myv cylinder does not require theexternal boosters required by assemblies of the prior art. My cylinderaccomplishes the punching operation without the flow ofhigh pressurefluid in any pipe external to the cylinder, My hydraulic piercingcylinder is less expensive to 7 construct than systems of the prior art.Further, it is less likely to develop leaks than are systems of theprior art.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to otherfeatures andsubcombinations. This is contemplated by and is Within the scope of ourclaims. It is z'furth'er obvious that various changes may be made indetails within the scope of our claims without departing'from'the spiritof our invention. It is therefore to be understood that our invention isnot to be limited to the specific details shown and described.

Having thus described my invention, what I claim is: 1;. 'A (hydraulicworking cylinder for performing an operation on a workpiece including incombination a cylinder body formed with a power chamber and stripperchamber, apower piston having a head mounted for reciprocation withinsaid power chamber, a tool, a die, means connecting said tool to one ofsaid power piston and cylinder body for movement therewith, meansconnecting said die to the other of said power piston and cylinder bodyfor movement therewith relative to said tool, a stripper plate, meansmounting said stripper plate for movement relative to said tool, astripper piston disposed in said stripper chamber and having a head anda plunger formed with a face, means providing communication between saidface and said power chamber, means for transmitting force from saidstripper piston to said stripper plate, a source of fluid underpressure, means for admitting fluid to said power chamber from saidsource to move said power piston and cylinder body away from each otherto move said stripper plate and said tool and said die toward eachother, said fluid being adapted to act on said plunger face to move saidstripper plate into engagement with said work before said tool engagesthe work, means responsive to the engagement of said stripper plate withthe work for admitting fluid from said source to said stripper chamberto move said plunger face toward said power chamber to boost thepressure within'said power chamber to drive said tool into engagementwith the work.

2. A hydraulic working cylinder as in claim 1 includingmeans foradmitting fluid into said power chamber to cause said tool and die tomove away from each afte a forming operation is complete.

3.'A hydraulic working cylinder for driving a tool to perform anoperation on a workpiece including in combination a cylinder body, meansdividing said body into a first chamber and a second chamber, saiddividing means being formed with an opening providing communicationbetween said chambers, a power piston disposed within; said firstchamber, means mounting said power piston' and said cylinder body formovement relative to each other,-a booster piston disposed in saidsecond chamber,

and'having a portion of reduced cross-sectional area extending into saidopening, a source of fluid under pressure,

means for admitting fluid-from said source into said first chamber tomove said piston and cylinder relative to each other, a sequence valveadapted to be actuated to admit fluid from said source to said secondchamber, a stripper plate carried by said cylinder body and adapted tobe moved into engagement with said workpiece as said cylinder and powerpiston move relative to each other and means responsive to theengagement of said stripper plate with said workpiece for actuating saidsequence valve to :admit fluid from-said source to actuate said boosterpiston to boost the pressure within said first chamber. a

4. A hydraulic working cylinder as in claim 3 in which said meansresponsive to the engagement of said stripper plate with said workpieceincludes means providing a .driving connection between said stripperplate and said booster piston.

5. A hydraulic working cylinder for driving a tool toward adie toperforman operation on a workpiece including in combination aframe, acylinderbody means dividing-said body into a first chamber and a second chamber,said dividing means being formed with an opening providing communicationbetween said chambers, a'powe'r piston disposed within said firstchamber, means mounting said piston for movement on said frame, meansmounting said cylinder for movement with respect to said frame and withrespect to said piston, means connecting said tool to-one of said powerpiston and cylinder body,-me,ans I connecting said die to the other ofsaid power piston and cylinder body, a booster piston disposed: insaid'se'condl chamberand having aportion of reduced cross-sectional areaextending into said opening, a source of fluid under pressure, means foradmitting fluid fromsaid source into said first chamber tomove saidpiston and cylinder relative to each other to cause, said tool to movetowardsaid fdie and means responsive to a predetermined amount of saidrelativemovement of said piston and cylinder body for admitting fluidfrom said source to said second chain v ber to actuate said "boosterpiston to boostthepressure Within said first chamber.

6. A hydraulic working cylinder for performing an operation on aworkpiece including in combination a cylinder body formed with a powerchamber and stripper chamber, a power piston having a head mounted forreciprocation within said power chamber, a tool, a die, means connectingsaid tool to one of said power piston and cylinder body for movementtherewith, means connecting said die to the other of said power pistonand cylinder body for movement therewith relative to said tool, astripper plate, means mounting said stripper plate for movement relativeto said tool, a stripper piston disposed in said stripper chamber andhaving a head and a plunger formed with a face, means providingcommunication between said face and said power chamber, means fortransmitting force from said stripper piston to said stripper plate, asource of fluid under pressure, means for admitting fluid from saidsource to said power chamber on one side of said-power piston head tomove said powerp'iston and cylinder body away from each other to movesaid stripper plate and tool and said die toward each other, said fluidacting on said plunger face to move said stripper plate intoenga'gementwith said work before said tool engages the work, means responsive tothe engagement of said stripper "plate with said work for admittingfluid from said source to said stripper chamber on one side of saidstripper pistonto move said plunger face toward said power chamber toboost the pressure within said power chamber to drive said tool intoengagement with the work, meansfor-admitting fluid from said source intosaid power chamberon the other side of said piston'to cause said tooland die to move away from each other after a forming'operation iscomplete and means for admitting fluid from said power chamber onsaidother side of said power piston to said stripper chamber on the otherside of said stripper piston head. i

7. A hydraulic working cylinder for driving a tool to perform anoperation on a workpiece including in combination a cylinder body havinga power chamber, a power piston disposed in said power chamber, a tool;a die, means connecting said tool to one of said piston and cylinder formovement therewith, means connectingsaid die to the other of said pistonand cylinder for movement therewith relative to said tool, saidworkpiece being disposed between said tool and said die, a source offluid under pressure, a reservoir, a control valve having a pair ofoutlet ports and adapted to be operated'to connectone of said ports tosaid supply and the other of said ports to said reservoir and to connectsaid one portto said reservoir and saidotherport to said supply, a pilotoperated check valve for connecting said one port to said chamberon oneside of said piston when 'said one port is connected to said supply tomove said piston and cylinder body relative to each other to move saidtool and die toward each other, said-check valve being'adapted to beoperated to connect said chamber on said one side of said piston to saidone port when said one port is connected tosaid reservoir, meansconnecting said'other port to said chamber on the other side of saidpiston, means responsive to an increase of pressure in said chamber onsaid"otherside of the piston for operating said check said cylinder bodyhaving a second chamber and an opening providing communication betweensaid second chamher and said powerchamber, a booster piston disposedin'said second chamber, said booster piston having a portion of reducedcross-sectional area disposed in said openeach other for causing anincrease in pressure in said power chamber on said one side of saidpower piston for operating said sequence valveto connect said one portto said second chamber.

valve when said other port is connected tosaid supply, 4

8. A hydraulic working cylinder for driving a tool to perform anoperation on a workpiece including in combination a cylinder body havinga power chamber, a power piston disposedin said power chamber, "a tool,a die, means connecting said tool mom of said piston and cylinder formovement therewith, means connecting said die to the other of saidpiston and cylinder for movement therewith relative to said tool, saidworkpiece being disp'osed between said tool and said die, a source offluid under pressure, a reservoir, a control valve having a pair ofoutlet ports and adapted to be operated to connect one of said ports tosaid supply and the other of said ports to said reservoir and to connectsaid one port to said reservoir and said other port to said supply, apilot operated check valve for connecting said one port to said chamberon one side of saidpiston when saidone port is connected to said supplyto move said piston and cylinder body relative to each other to movesaid tool and die toward each other, said check valve being adapted tobe operated to connect said chamber on said one side of said piston tosaid one port when said one port is connected to said reservoir, meansconnecting said other porttosaid chamber on the other side of saidpiston, means responsive to an increase of pressure in said chamberonsaid other side of the piston for operating said check valve when saidother port is connected to said supply, said cylin'der body having asecond chamber and an opening providing communication between saidsecond chamber and said power chamber, a booster piston disposed in saidsecond chamber, said booster piston having a portionof reducedcross-sectional area disposed in said opening, a sequence valve adaptedto be operated to connect said one port to said second chamber, meansresponsive to a predetermined movement of said power piston and saidcylinder body in moving said tool and die toward each other for causinga pressure increase in said power chamher on said one side of said powerpiston for operating saidsequence valve to connect said one port to saidsecond chamber, and a check valve for by-passing said sequencevalve whensaid other port is connected to'said supply.

References Cited in the file of this patent UNITED STATES PATENTS2,324,149 Gray July 13, 1943 2,351,872 Parker June 20, 1944 2,403,912Doll; July 16, 1946 2,534,292 Mueller Dec. 19, 1950 2,576,584 Ernst Nov.27, 1951 2,758,652 Novingeret al 'Aug. '14, 1956 2,765,036 Harper Oct.2, 1956 2,776,540 Kraujalis Jan. 8, 1957 FOREIGN PATENTS 551,059Belgian; Sept. 29, 1956

